Musk Slashes Lunar Refueling Launch Count to Six or Eight

Twenty-two Starship launches. That is the number cited by a NASA safety advisory panel as the likely requirement to fuel a lunar lander for the 2028 Artemis IV mission. Elon Musk says the real figure will be far lower, placing the necessary count at just six to eight flights.

The disagreement surfaced after the Aerospace Safety Advisory Panel held its quarterly public meeting on Thursday. Panel member Charlie Precourt, a former NASA astronaut, flagged the orbital fueling process as a primary risk for the crewed lunar landing. "We need to keep our eyes on numerous required fuelings for the lander," Precourt told the panel. "I think the last estimate is around 22 flights."

Musk responded to the remark after Ars Technica reporter Eric Berger shared the comment on X. "That's way too high," Musk wrote. "Actual number will be more like 6 to 8."

The discrepancy centers on the technical constraints of using Starship for lunar missions. The rocket consumes nearly all its propellant reaching Earth orbit, making it impossible to reach the Moon without a top-up. SpaceX plans to use an orbital depot, a Starship configured as a storage tank, which is launched first. Tanker Starships then fly sequentially, dock, and transfer their remaining propellant. Once the depot is full, the lunar lander launches, refuels, and departs.

The total number of launches directly impacts mission cost and schedule. Each tanker flight is a full rocket launch, adding time, expense, and potential points of failure. Berger estimated that even with two Starship launches per week by the end of 2027, filling a depot to the panel's 22-flight specification would take approximately three months.

The variance in estimates likely stems from assumptions about vehicle performance and propellant loss. NASA's figure appears to be based on Starship's current lift capacity, while Musk's lower range assumes a more capable version. Cold propellant also boils off slowly in orbit and during transfers, reducing the effective payload of each tanker. Musk has disputed high launch counts before, calling a 2021 government estimate of 16 launches "extremely unlikely."

Precourt noted that Artemis IV involves "a large number of firsts." He credited NASA Administrator Jared Isaacman's team for clearing obstacles for both SpaceX and Blue Origin. Blue Origin's Blue Moon lander does not rely on orbital refueling for its initial mission, a key difference in the two companies' approaches to lunar architecture.